Included in this section:
Chemical
Storage
Ideally, one
chemical/biological storage room under the supervision of a qualified
person is essential for each school.
The storage room should have adequate security.
Safety facilities should include the following:
.
Approved fire extinguishers and containers of sand and soda
positioned near an escape route.
. Spill
control and clean-up materials.
. Master
control shut-off valves for gas, water, and electricity.
. Approved
eye/face wash.
. Shower.
. Smoke
detector.
. Forced
ventilation from floor to ceiling with exhaust above roof level.
. Lip-edged
wooden shelving secured to wall with top shelf below eye level.
. A
communication system to the main office or emergency center.
The
alphabetical method of storing chemicals presents hazards because
chemicals which react violently with each other may be stored in close
proximity.
Flammables
must be stored in a separate flammable cabinet. A separate cabinet is also required for certain acids.
Flinn Catalog identifies which acids must be isolated.
Chemicals can be sorted according to the scheme presented in the
Flinn Chemical Catalog
Reference Manual. The Flinn Manual suggests sorting the chemicals into ORGANIC
and
INORGANIC
groupings which are then further sorted into compatible families as
suggested below:
INORGANIC ORGANIC
1.
Metals, hydrides
1. Acids, anhydrides,
peracids
2.
Halides, sulfates,
sulfites, thiosulfates 2.
Alcohols, glycols, amines, imines,
3.
Amides, nitrates*
nitrites*, 3.
Hydrocarbons, esters, aldehydes
nitric
acid 4.
Ethers*, ketones, ketenes,
4.
Hydroxides, oxides,
silicates, carbonates, halogenated
hydrocarbons,carbon
carbon
ethylene oxide
5.
Sulfides, selenides,
phosphides, carbides,
5.
Epoxy compounds, isocyanates
nitrides
6.
Peroxides,hydroperoxides, azides*
6.
Hypochlorites, soln, and
hydrogen peroxide 7.
Sulfur
7.
Borates, chromates,
manganates, 8.
Phenols, cresols
permanganates
8.
Acids (except nitric)
9.
Sulfur, phosphorus*,
arsenic, phorphorus
pentoxide*
* These chemicals
deserve special attention due to their potential instability.
Consult the Flinn Chemical Catalog Reference Manual for diagrams
of suggested shelf
storage patterns for inorganic and organic chemicals.
NOTE:
Be sure to follow local fire codes when storing flammable
chemicals in separate cabinets.
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Purchase,
Use and Disposal of Chemicals
It is suggested that
the following guidelines be followed when purchasing, using and
disposing of chemicals.
. If
possible, purchase chemicals in class-size quantities only.
. Label
all chemicals accurately with date of receipt or preparation, the
initials of the person responsible, and pertinent precautionary
information on handling.
. Follow
all directions for disposing of residues and unused portions of
reagents. (see Flinn
Disposal guide.)
. Properly
store flammable liquids in small quantities in containers with a
provision for bonding and receiving vessels when the liquid is
transferred.
. Never
open a reagent package until the label has been read and completely
understood.
. Read
the Material Safety Data Sheet on hand before using a chemical.
In regards to disposing of unwanted or waste chemicals:
. Prepare
a complete list of chemicals of which you wish to dispose.
. Classify
each of the chemicals on the disposal list into a hazardous or
non-hazardous waste chemical.
. Unlabeled
bottles (a special problem) must be identified to the extent that they
can be classified as hazardous or non-hazardous wastes.
(Some laboratories will analyze a mystery bottle for a fee.)
. When
in doubt concerning the disposal of unwanted or waste chemicals, contact
the Office of Environmental Management, Akron Public Schools.
. The Office of Environmental Management
will arrange for the disposal of unwanted chemicals twice a year.
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Special
Note: Disposal of Wastes in
Sanitary Sewers
Small quantities of some wastes can be disposed of in sanitary
(not storm) sewers. However,
this practice is discouraged. The quantities should be limited to a few
hundred grams or milliliters, flushing with large quantities of water to
achieve high dilution.
Inorganic salts in which both the cation and anion are relatively
non-toxic are generally permissible for drain disposal if they are
soluble to a degree of a few percent.
Check local regulations for possible restrictions.
Mineral acids or bases should be neutralized before drain
disposal.
Don’t throw any unwanted chemicals down the drain or in the
wastebasket. Some organic
compounds that are reasonably soluble in water are suitable for drain
disposal. Again, check
local regulations if in doubt. Generally,
short chain alcoholsaldehydes, amides, amines, carboxylic acids, esters,
ethers, and ketones are suitable. One
exception would be low boiling point flammable liquids, such as diethyl
ether. Other exceptions
include explosives like azides or peroxides.
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Chemical
Spills
Chemical spills occur
in any laboratory. In order
to minimize health, property, and fire hazards, the following supplies
should be on hand to deal with spills:
.
Neutralizing agents, such as sodium carbonate
.
Absorbants, such as sand and vermiculite
.
Paper towels
.
Sponges
.
Mop and bucket
.
Broom and dust pan
.
Rubber gloves
.
Safety glasses
.
Apron
.
Plastic garbage bags
.
Mercury sponge
.
Seamless polyethylene bottle for mercury spills
If
the spill occurs, follow these priorities:
.
Attend to any person whose skin or clothing may have been
affected.
.
Notify others in the room to stay clear of the spill.
.
Avoid breathing the vapor if it is a liquid spill.
Open windows and/or
turn on exhaust fans.
.
Evacuate classroom.
.
Clean up the spill wearing appropriate protective clothing.
.
Seek information on spill management (See Flinn, MSDS, or
Emergency
Response Guide).
Solid spills of low toxicity materials can be swept up using a
broom and dust pan. Place the material in a plastic bag if it is to be placed in
a solid waste container. Do
not dump it directly into a metal waste can!
Dispose of waste according to safe disposal procedures.
If a liquid spill* occurs, wear rubber gloves and use the
following procedure:
.
For inorganic acids or bases, use a neutralizing agent, such as
soda ash.
For
other materials, use dry sand, vermiculite, or paper towels.
(NOTE:
Do not use paper towels for concentrated sulfuric acid spills.)
.
Carefully clean any splashed liquid from other bottles or
apparatus.
.
Mop up the spill.
.
Dispose of residues according to safe disposal procedures.
*
Mercury spills present a special type of hazard due to the acute
and chronic toxicity of mercury vapors.
Flinn (1998) makes the following suggestions for cleaning up
mercury spills:
. Immediately
following a mercury spill or thermometer breakage, provide maximum
ventilation by opening doors and windows.
. Never
sweep the spill with a broom. Attempt,
to the extent possible, to avoid creating free mercury vapor. Avoid contaminating brooms, your shoes, or other items in the
area. Put plastic bags over
your shoes if you must walk in the spill area.
. Push
the pools of mercury together.
. Pick
up the pools with a closed device like a medicine dropper.
Transfer the picked up droplets to a seamless polyethylene or
polypropylene bottle.
Once the visible droplets have been found, picked up, and placed
in a seamless plastic bottle, the remaining hidden droplets can be
cleaned up in the following manner:
. Zinc
metal powder can be spread about the spill area.
If the mercury is clean, the zinc and mercury will form a safe
amalgam which can be easily collected and disposed of in the same
fashion as the elemental mercury.
. Go
over the area with a mercury sponge.
A mercury sponge contains high surface area zinc fibers.
Again, an amalgam will form if the mercury is clean.
. A
mercury vacuum cleaner is available from Flinn on a rental basis. Never use a standard
vacuum cleaner! This
will create a mercury aerosol which will be spewed into the surrounding
area.
. It
is strongly suggested that mercury thermometers be eliminated for most
laboratory use.
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Safety
Products in the Chemistry Lab
There are several safety products which are essential to the
proper operation of a chemistry program.
The following is a brief description of those products which
should be included in a safety inventory:
Eye Protection: The
State of Ohio requires that each student has
personal eye protection.
The material should conform to America
National Standard Institute (ANSI)
Z87.1-1979 standards for use, durability,
and cleaning.
Appropriate chemical resistant goggles are available through the
Akron Public Schools Warehouse.
Eye-wash stations should be made available with signs posted in
the lab identifying their location.
All students should be instructed in the use of the eye-wash
stations.
Fire Extinguishers:
The four standard types of fire extinguishers are (1) Class A
- used for paper and trash, (2) Class B - used for flammable liquids,
(3) Class C - used for electrical fires, and (4) Class D - used for
flammable metals. The ideal
extinguisher is a carbon dioxide or dry powder unit rated for Class A, B
and C fires.
Fire extinguishers must be recharged on a regular basis. The chemistry teacher should inspect the condition of the
unit at least once per week. Extinguishers
are recharged annually. Make
sure that the proper unit is returned to the same lab position.
Provide proper instruction on the use of a fire extinguisher to
the class prior to the first laboratory exercise at the beginning of
each school year.
First Aid:
First-aid kits should be available in the lab with the
location clearly marked and identified.
The instructor should take inventory of the kit on a regular
basis. The instructor and
the students should be aware of the proper use of the contents of the
first-aid kit.
Miscellaneous: There are several other items of safety which a chemistry
lab should contain. Among
them are an emergency shower, safety signs, safety posters, bottle
carriers, storage cans, and labels.
It is advisable that the instructor inform the students of the
proper use of these items.
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Safety
in the Chemistry Lab
The Facility:
. Take
note of any structural abnormality or unsafe condition in the classroom
or storeroom and report it in writing to the appropriate authority.
. Chemistry
facilities should be used for chemistry classes only.
Equipment Use:
. Broken
glassware is to be disposed of in a container separate from paper and
other wastes.
. All
rough glass edges should be fire polished.
. Do
not have students insert glass tubing.
Teachers should do this procedure.
When inserting glass tubing into a rubber stopper, lubricate the
tubing with glycerine, wrap the tubing with a towel, and gently twist
the tubing into the stopper hole.
. Water
from sinks should never be turned on to the highest degree.
Gentle washing of materials prevents splashing.
.
Check charge level of fire extinguishers.
Recharge, if necessary. After
recharging, make sure that the proper extinguisher is returned to the
lab.
. Maintain
emergency lighting (e.g., flashlight).
. Maintain
a file of instruction/operating manuals for all science equipment.
. Check
for stability of glassware support.
Chemicals:
. When
transferring a chemical into a secondary container the following
information should be included on the label:
chemical name, formula, concentration, solvent (if solution),
hazard warning, name or initials of person responsible for transfer.
. When
performing lab activities involving toxic vapors, flammable gases and
noxious odors, use a fume hood.
. Containers
of chemicals should be carried with two hands.
Never grab a container from the top only.
. Maintain
the smallest amount of chemicals needed for individual projects
throughout the year.
Teacher
Responsibility:
. Do
not permit horseplay in the lab. Maintain
control.
. Instruct
students on the use of all safety equipment in the room.
. Identify
the locations of all safety equipment by appropriate signs.
.
Group sizes should conform to a number which can perform the
experiment safely.
. Plan
enough time for the experiment and clean up of materials.
. Develop
safety lessons with objectives that can be measured.
. Develop
an accident plan.
. Instruct
students never to eat or drink in the classroom.
. All
gas valves in the lab should be turned off at the end of the lab. The master gas valve - if one exists - should be turned off
at the end of the day.
. Chemicals
should be stored under lock and key when not in use.
. Students
should never be left unsupervised.
. The
lab should always be locked when not in use.
. All
students performing scientific experiments that involve a hazard to the
eye must wear appropriate eye protection.
This rule must include visitors.
. Full
length aprons or lab coats, which are designed to protect from chemical
hazards, must be worn when appropriate.
. Gloves,
which are designed to withstand chemical hazards, should be worn when
appropriate.
. Chemicals
should be stored in approved containers and storage devices.
. Do
not smoke in the lab, storage areas, or adjacent office areas.
. Instructors
should weigh the educational value of an experiment with the potential
risks involved.
. Take
a periodic inventory of the lab safety devices and report defective
devices to the appropriate authority.
Teacher
Responsibility: (continued)
. Take
note of any structural abnormality or unsafe condition in the classroom
and report it to the appropriate authority.
. Observe
students for any abnormal physical or mental activity before, during, or
after an experiment. Do not
allow any student who displays abnormal physiological characteristics to
perform an experiment.
. Develop
a plan to secure the lab during emergency drills.
. Potential
hazards should be identified prior to an experiment.
. Include
a list of safety rules with a substitute's lesson plan.
However, it is advisable a substitute monitor a lab activity.
.
Document safety violations and report safety concerns in writing
to the appropriate
authorities.
. Always
store chemicals with labels in the forward, readable, position.
. Do
not use unlabeled chemicals.
. Use
a grease pencil for labeling glassware.
.
Report missing/stolen materials to the principal immediately.
Student
Responsibility:
.
Report all accidents to the instructor, no matter the degree.
. Never
mix chemicals without a defined procedure.
. Never
drink water from any lab glassware.
. Never
point the open end of a test tube at yourself or other students.
. Never
smell the contents of a test tube unless instructed to do so as a part
of the experiment. When so
instructed, never bring the container directly to the nose, but wave
your hand over it and move the air toward your nose.
. Work
areas should be uncluttered and free of combustible materials.
. Never
touch any part of your face while working in the lab.
. Never
taste a chemical in the lab.
. All
students should wash their hands at the end of the experiment.
. Glassware
and equipment should not be placed at the edge of a table top or work
space.
Student
Responsibility (continued)
. Never
leave experiments while in progress.
. It
is advisable that contact lenses not be worn during an experiment
without the teacher’s knowledge.
. Long
hair should be pulled back and fastened during labs.
. Perform
only authorized experiments as assigned by the instructor.
. Inform
the instructor of any breakage, spills, or contamination at once.
. Sinks
are not to be used to dispose of matches or paper.
. Do
not wear jewelry when working in the lab.
. Always
read labels/MSDS before handling any chemical.
. If
instructions are unclear, ask your instructor for clarification.
Do's
and Don'ts:
. Allow
falling objects to fall; never try to grab a falling object.
. Allow
glassware to cool after heating by placing it on a special surface. Do not submerge hot glassware in water.
.
Always pour acid into water.
Never pour water into acid.
.
Never pipette with your mouth.
Use a pipette bulb or an automatic filler.
.
Asbestos should never be used in the lab.
.
Known carcinogens should never be used in the lab.
.
At no time should students be given hazardous chemicals to take
home.
. At
no time should the teacher accept unsolicited chemicals without approval
of
administrative
personnel. Some agencies use schools as “dumping grounds” to rid
themselves of liability. This
practice can increase the hazards for school personnel and students and
increase disposal costs.
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